1 // SPDX-License-Identifier: GPL-2.0-only
2 #define pr_fmt(fmt) "IPsec: " fmt
3
4 #include <crypto/aead.h>
5 #include <crypto/authenc.h>
6 #include <linux/err.h>
7 #include <linux/module.h>
8 #include <net/ip.h>
9 #include <net/xfrm.h>
10 #include <net/esp.h>
11 #include <linux/scatterlist.h>
12 #include <linux/kernel.h>
13 #include <linux/pfkeyv2.h>
14 #include <linux/rtnetlink.h>
15 #include <linux/slab.h>
16 #include <linux/spinlock.h>
17 #include <linux/in6.h>
18 #include <net/icmp.h>
19 #include <net/protocol.h>
20 #include <net/udp.h>
21 #include <net/tcp.h>
22 #include <net/espintcp.h>
23
24 #include <linux/highmem.h>
25
26 struct esp_skb_cb {
27 struct xfrm_skb_cb xfrm;
28 void *tmp;
29 };
30
31 struct esp_output_extra {
32 __be32 seqhi;
33 u32 esphoff;
34 };
35
36 #define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0]))
37
38 /*
39 * Allocate an AEAD request structure with extra space for SG and IV.
40 *
41 * For alignment considerations the IV is placed at the front, followed
42 * by the request and finally the SG list.
43 *
44 * TODO: Use spare space in skb for this where possible.
45 */
esp_alloc_tmp(struct crypto_aead * aead,int nfrags,int extralen)46 static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int extralen)
47 {
48 unsigned int len;
49
50 len = extralen;
51
52 len += crypto_aead_ivsize(aead);
53
54 if (len) {
55 len += crypto_aead_alignmask(aead) &
56 ~(crypto_tfm_ctx_alignment() - 1);
57 len = ALIGN(len, crypto_tfm_ctx_alignment());
58 }
59
60 len += sizeof(struct aead_request) + crypto_aead_reqsize(aead);
61 len = ALIGN(len, __alignof__(struct scatterlist));
62
63 len += sizeof(struct scatterlist) * nfrags;
64
65 return kmalloc(len, GFP_ATOMIC);
66 }
67
esp_tmp_extra(void * tmp)68 static inline void *esp_tmp_extra(void *tmp)
69 {
70 return PTR_ALIGN(tmp, __alignof__(struct esp_output_extra));
71 }
72
esp_tmp_iv(struct crypto_aead * aead,void * tmp,int extralen)73 static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int extralen)
74 {
75 return crypto_aead_ivsize(aead) ?
76 PTR_ALIGN((u8 *)tmp + extralen,
77 crypto_aead_alignmask(aead) + 1) : tmp + extralen;
78 }
79
esp_tmp_req(struct crypto_aead * aead,u8 * iv)80 static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv)
81 {
82 struct aead_request *req;
83
84 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
85 crypto_tfm_ctx_alignment());
86 aead_request_set_tfm(req, aead);
87 return req;
88 }
89
esp_req_sg(struct crypto_aead * aead,struct aead_request * req)90 static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead,
91 struct aead_request *req)
92 {
93 return (void *)ALIGN((unsigned long)(req + 1) +
94 crypto_aead_reqsize(aead),
95 __alignof__(struct scatterlist));
96 }
97
esp_ssg_unref(struct xfrm_state * x,void * tmp)98 static void esp_ssg_unref(struct xfrm_state *x, void *tmp)
99 {
100 struct crypto_aead *aead = x->data;
101 int extralen = 0;
102 u8 *iv;
103 struct aead_request *req;
104 struct scatterlist *sg;
105
106 if (x->props.flags & XFRM_STATE_ESN)
107 extralen += sizeof(struct esp_output_extra);
108
109 iv = esp_tmp_iv(aead, tmp, extralen);
110 req = esp_tmp_req(aead, iv);
111
112 /* Unref skb_frag_pages in the src scatterlist if necessary.
113 * Skip the first sg which comes from skb->data.
114 */
115 if (req->src != req->dst)
116 for (sg = sg_next(req->src); sg; sg = sg_next(sg))
117 put_page(sg_page(sg));
118 }
119
120 #ifdef CONFIG_INET_ESPINTCP
121 struct esp_tcp_sk {
122 struct sock *sk;
123 struct rcu_head rcu;
124 };
125
esp_free_tcp_sk(struct rcu_head * head)126 static void esp_free_tcp_sk(struct rcu_head *head)
127 {
128 struct esp_tcp_sk *esk = container_of(head, struct esp_tcp_sk, rcu);
129
130 sock_put(esk->sk);
131 kfree(esk);
132 }
133
esp_find_tcp_sk(struct xfrm_state * x)134 static struct sock *esp_find_tcp_sk(struct xfrm_state *x)
135 {
136 struct xfrm_encap_tmpl *encap = x->encap;
137 struct esp_tcp_sk *esk;
138 __be16 sport, dport;
139 struct sock *nsk;
140 struct sock *sk;
141
142 sk = rcu_dereference(x->encap_sk);
143 if (sk && sk->sk_state == TCP_ESTABLISHED)
144 return sk;
145
146 spin_lock_bh(&x->lock);
147 sport = encap->encap_sport;
148 dport = encap->encap_dport;
149 nsk = rcu_dereference_protected(x->encap_sk,
150 lockdep_is_held(&x->lock));
151 if (sk && sk == nsk) {
152 esk = kmalloc(sizeof(*esk), GFP_ATOMIC);
153 if (!esk) {
154 spin_unlock_bh(&x->lock);
155 return ERR_PTR(-ENOMEM);
156 }
157 RCU_INIT_POINTER(x->encap_sk, NULL);
158 esk->sk = sk;
159 call_rcu(&esk->rcu, esp_free_tcp_sk);
160 }
161 spin_unlock_bh(&x->lock);
162
163 sk = inet_lookup_established(xs_net(x), &tcp_hashinfo, x->id.daddr.a4,
164 dport, x->props.saddr.a4, sport, 0);
165 if (!sk)
166 return ERR_PTR(-ENOENT);
167
168 if (!tcp_is_ulp_esp(sk)) {
169 sock_put(sk);
170 return ERR_PTR(-EINVAL);
171 }
172
173 spin_lock_bh(&x->lock);
174 nsk = rcu_dereference_protected(x->encap_sk,
175 lockdep_is_held(&x->lock));
176 if (encap->encap_sport != sport ||
177 encap->encap_dport != dport) {
178 sock_put(sk);
179 sk = nsk ?: ERR_PTR(-EREMCHG);
180 } else if (sk == nsk) {
181 sock_put(sk);
182 } else {
183 rcu_assign_pointer(x->encap_sk, sk);
184 }
185 spin_unlock_bh(&x->lock);
186
187 return sk;
188 }
189
esp_output_tcp_finish(struct xfrm_state * x,struct sk_buff * skb)190 static int esp_output_tcp_finish(struct xfrm_state *x, struct sk_buff *skb)
191 {
192 struct sock *sk;
193 int err;
194
195 rcu_read_lock();
196
197 sk = esp_find_tcp_sk(x);
198 err = PTR_ERR_OR_ZERO(sk);
199 if (err)
200 goto out;
201
202 bh_lock_sock(sk);
203 if (sock_owned_by_user(sk))
204 err = espintcp_queue_out(sk, skb);
205 else
206 err = espintcp_push_skb(sk, skb);
207 bh_unlock_sock(sk);
208
209 out:
210 rcu_read_unlock();
211 return err;
212 }
213
esp_output_tcp_encap_cb(struct net * net,struct sock * sk,struct sk_buff * skb)214 static int esp_output_tcp_encap_cb(struct net *net, struct sock *sk,
215 struct sk_buff *skb)
216 {
217 struct dst_entry *dst = skb_dst(skb);
218 struct xfrm_state *x = dst->xfrm;
219
220 return esp_output_tcp_finish(x, skb);
221 }
222
esp_output_tail_tcp(struct xfrm_state * x,struct sk_buff * skb)223 static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb)
224 {
225 int err;
226
227 local_bh_disable();
228 err = xfrm_trans_queue_net(xs_net(x), skb, esp_output_tcp_encap_cb);
229 local_bh_enable();
230
231 /* EINPROGRESS just happens to do the right thing. It
232 * actually means that the skb has been consumed and
233 * isn't coming back.
234 */
235 return err ?: -EINPROGRESS;
236 }
237 #else
esp_output_tail_tcp(struct xfrm_state * x,struct sk_buff * skb)238 static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb)
239 {
240 kfree_skb(skb);
241
242 return -EOPNOTSUPP;
243 }
244 #endif
245
esp_output_done(struct crypto_async_request * base,int err)246 static void esp_output_done(struct crypto_async_request *base, int err)
247 {
248 struct sk_buff *skb = base->data;
249 struct xfrm_offload *xo = xfrm_offload(skb);
250 void *tmp;
251 struct xfrm_state *x;
252
253 if (xo && (xo->flags & XFRM_DEV_RESUME)) {
254 struct sec_path *sp = skb_sec_path(skb);
255
256 x = sp->xvec[sp->len - 1];
257 } else {
258 x = skb_dst(skb)->xfrm;
259 }
260
261 tmp = ESP_SKB_CB(skb)->tmp;
262 esp_ssg_unref(x, tmp);
263 kfree(tmp);
264
265 if (xo && (xo->flags & XFRM_DEV_RESUME)) {
266 if (err) {
267 XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR);
268 kfree_skb(skb);
269 return;
270 }
271
272 skb_push(skb, skb->data - skb_mac_header(skb));
273 secpath_reset(skb);
274 xfrm_dev_resume(skb);
275 } else {
276 if (!err &&
277 x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP)
278 esp_output_tail_tcp(x, skb);
279 else
280 xfrm_output_resume(skb, err);
281 }
282 }
283
284 /* Move ESP header back into place. */
esp_restore_header(struct sk_buff * skb,unsigned int offset)285 static void esp_restore_header(struct sk_buff *skb, unsigned int offset)
286 {
287 struct ip_esp_hdr *esph = (void *)(skb->data + offset);
288 void *tmp = ESP_SKB_CB(skb)->tmp;
289 __be32 *seqhi = esp_tmp_extra(tmp);
290
291 esph->seq_no = esph->spi;
292 esph->spi = *seqhi;
293 }
294
esp_output_restore_header(struct sk_buff * skb)295 static void esp_output_restore_header(struct sk_buff *skb)
296 {
297 void *tmp = ESP_SKB_CB(skb)->tmp;
298 struct esp_output_extra *extra = esp_tmp_extra(tmp);
299
300 esp_restore_header(skb, skb_transport_offset(skb) + extra->esphoff -
301 sizeof(__be32));
302 }
303
esp_output_set_extra(struct sk_buff * skb,struct xfrm_state * x,struct ip_esp_hdr * esph,struct esp_output_extra * extra)304 static struct ip_esp_hdr *esp_output_set_extra(struct sk_buff *skb,
305 struct xfrm_state *x,
306 struct ip_esp_hdr *esph,
307 struct esp_output_extra *extra)
308 {
309 /* For ESN we move the header forward by 4 bytes to
310 * accommodate the high bits. We will move it back after
311 * encryption.
312 */
313 if ((x->props.flags & XFRM_STATE_ESN)) {
314 __u32 seqhi;
315 struct xfrm_offload *xo = xfrm_offload(skb);
316
317 if (xo)
318 seqhi = xo->seq.hi;
319 else
320 seqhi = XFRM_SKB_CB(skb)->seq.output.hi;
321
322 extra->esphoff = (unsigned char *)esph -
323 skb_transport_header(skb);
324 esph = (struct ip_esp_hdr *)((unsigned char *)esph - 4);
325 extra->seqhi = esph->spi;
326 esph->seq_no = htonl(seqhi);
327 }
328
329 esph->spi = x->id.spi;
330
331 return esph;
332 }
333
esp_output_done_esn(struct crypto_async_request * base,int err)334 static void esp_output_done_esn(struct crypto_async_request *base, int err)
335 {
336 struct sk_buff *skb = base->data;
337
338 esp_output_restore_header(skb);
339 esp_output_done(base, err);
340 }
341
esp_output_udp_encap(struct sk_buff * skb,int encap_type,struct esp_info * esp,__be16 sport,__be16 dport)342 static struct ip_esp_hdr *esp_output_udp_encap(struct sk_buff *skb,
343 int encap_type,
344 struct esp_info *esp,
345 __be16 sport,
346 __be16 dport)
347 {
348 struct udphdr *uh;
349 __be32 *udpdata32;
350 unsigned int len;
351
352 len = skb->len + esp->tailen - skb_transport_offset(skb);
353 if (len + sizeof(struct iphdr) > IP_MAX_MTU)
354 return ERR_PTR(-EMSGSIZE);
355
356 uh = (struct udphdr *)esp->esph;
357 uh->source = sport;
358 uh->dest = dport;
359 uh->len = htons(len);
360 uh->check = 0;
361
362 *skb_mac_header(skb) = IPPROTO_UDP;
363
364 if (encap_type == UDP_ENCAP_ESPINUDP_NON_IKE) {
365 udpdata32 = (__be32 *)(uh + 1);
366 udpdata32[0] = udpdata32[1] = 0;
367 return (struct ip_esp_hdr *)(udpdata32 + 2);
368 }
369
370 return (struct ip_esp_hdr *)(uh + 1);
371 }
372
373 #ifdef CONFIG_INET_ESPINTCP
esp_output_tcp_encap(struct xfrm_state * x,struct sk_buff * skb,struct esp_info * esp)374 static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x,
375 struct sk_buff *skb,
376 struct esp_info *esp)
377 {
378 __be16 *lenp = (void *)esp->esph;
379 struct ip_esp_hdr *esph;
380 unsigned int len;
381 struct sock *sk;
382
383 len = skb->len + esp->tailen - skb_transport_offset(skb);
384 if (len > IP_MAX_MTU)
385 return ERR_PTR(-EMSGSIZE);
386
387 rcu_read_lock();
388 sk = esp_find_tcp_sk(x);
389 rcu_read_unlock();
390
391 if (IS_ERR(sk))
392 return ERR_CAST(sk);
393
394 *lenp = htons(len);
395 esph = (struct ip_esp_hdr *)(lenp + 1);
396
397 return esph;
398 }
399 #else
esp_output_tcp_encap(struct xfrm_state * x,struct sk_buff * skb,struct esp_info * esp)400 static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x,
401 struct sk_buff *skb,
402 struct esp_info *esp)
403 {
404 return ERR_PTR(-EOPNOTSUPP);
405 }
406 #endif
407
esp_output_encap(struct xfrm_state * x,struct sk_buff * skb,struct esp_info * esp)408 static int esp_output_encap(struct xfrm_state *x, struct sk_buff *skb,
409 struct esp_info *esp)
410 {
411 struct xfrm_encap_tmpl *encap = x->encap;
412 struct ip_esp_hdr *esph;
413 __be16 sport, dport;
414 int encap_type;
415
416 spin_lock_bh(&x->lock);
417 sport = encap->encap_sport;
418 dport = encap->encap_dport;
419 encap_type = encap->encap_type;
420 spin_unlock_bh(&x->lock);
421
422 switch (encap_type) {
423 default:
424 case UDP_ENCAP_ESPINUDP:
425 case UDP_ENCAP_ESPINUDP_NON_IKE:
426 esph = esp_output_udp_encap(skb, encap_type, esp, sport, dport);
427 break;
428 case TCP_ENCAP_ESPINTCP:
429 esph = esp_output_tcp_encap(x, skb, esp);
430 break;
431 }
432
433 if (IS_ERR(esph))
434 return PTR_ERR(esph);
435
436 esp->esph = esph;
437
438 return 0;
439 }
440
esp_output_head(struct xfrm_state * x,struct sk_buff * skb,struct esp_info * esp)441 int esp_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
442 {
443 u8 *tail;
444 int nfrags;
445 int esph_offset;
446 struct page *page;
447 struct sk_buff *trailer;
448 int tailen = esp->tailen;
449
450 /* this is non-NULL only with TCP/UDP Encapsulation */
451 if (x->encap) {
452 int err = esp_output_encap(x, skb, esp);
453
454 if (err < 0)
455 return err;
456 }
457
458 if (ALIGN(tailen, L1_CACHE_BYTES) > PAGE_SIZE ||
459 ALIGN(skb->data_len, L1_CACHE_BYTES) > PAGE_SIZE)
460 goto cow;
461
462 if (!skb_cloned(skb)) {
463 if (tailen <= skb_tailroom(skb)) {
464 nfrags = 1;
465 trailer = skb;
466 tail = skb_tail_pointer(trailer);
467
468 goto skip_cow;
469 } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS)
470 && !skb_has_frag_list(skb)) {
471 int allocsize;
472 struct sock *sk = skb->sk;
473 struct page_frag *pfrag = &x->xfrag;
474
475 esp->inplace = false;
476
477 allocsize = ALIGN(tailen, L1_CACHE_BYTES);
478
479 spin_lock_bh(&x->lock);
480
481 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
482 spin_unlock_bh(&x->lock);
483 goto cow;
484 }
485
486 page = pfrag->page;
487 get_page(page);
488
489 tail = page_address(page) + pfrag->offset;
490
491 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
492
493 nfrags = skb_shinfo(skb)->nr_frags;
494
495 __skb_fill_page_desc(skb, nfrags, page, pfrag->offset,
496 tailen);
497 skb_shinfo(skb)->nr_frags = ++nfrags;
498
499 pfrag->offset = pfrag->offset + allocsize;
500
501 spin_unlock_bh(&x->lock);
502
503 nfrags++;
504
505 skb->len += tailen;
506 skb->data_len += tailen;
507 skb->truesize += tailen;
508 if (sk && sk_fullsock(sk))
509 refcount_add(tailen, &sk->sk_wmem_alloc);
510
511 goto out;
512 }
513 }
514
515 cow:
516 esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb);
517
518 nfrags = skb_cow_data(skb, tailen, &trailer);
519 if (nfrags < 0)
520 goto out;
521 tail = skb_tail_pointer(trailer);
522 esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset);
523
524 skip_cow:
525 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
526 pskb_put(skb, trailer, tailen);
527
528 out:
529 return nfrags;
530 }
531 EXPORT_SYMBOL_GPL(esp_output_head);
532
esp_output_tail(struct xfrm_state * x,struct sk_buff * skb,struct esp_info * esp)533 int esp_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
534 {
535 u8 *iv;
536 int alen;
537 void *tmp;
538 int ivlen;
539 int assoclen;
540 int extralen;
541 struct page *page;
542 struct ip_esp_hdr *esph;
543 struct crypto_aead *aead;
544 struct aead_request *req;
545 struct scatterlist *sg, *dsg;
546 struct esp_output_extra *extra;
547 int err = -ENOMEM;
548
549 assoclen = sizeof(struct ip_esp_hdr);
550 extralen = 0;
551
552 if (x->props.flags & XFRM_STATE_ESN) {
553 extralen += sizeof(*extra);
554 assoclen += sizeof(__be32);
555 }
556
557 aead = x->data;
558 alen = crypto_aead_authsize(aead);
559 ivlen = crypto_aead_ivsize(aead);
560
561 tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen);
562 if (!tmp)
563 goto error;
564
565 extra = esp_tmp_extra(tmp);
566 iv = esp_tmp_iv(aead, tmp, extralen);
567 req = esp_tmp_req(aead, iv);
568 sg = esp_req_sg(aead, req);
569
570 if (esp->inplace)
571 dsg = sg;
572 else
573 dsg = &sg[esp->nfrags];
574
575 esph = esp_output_set_extra(skb, x, esp->esph, extra);
576 esp->esph = esph;
577
578 sg_init_table(sg, esp->nfrags);
579 err = skb_to_sgvec(skb, sg,
580 (unsigned char *)esph - skb->data,
581 assoclen + ivlen + esp->clen + alen);
582 if (unlikely(err < 0))
583 goto error_free;
584
585 if (!esp->inplace) {
586 int allocsize;
587 struct page_frag *pfrag = &x->xfrag;
588
589 allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES);
590
591 spin_lock_bh(&x->lock);
592 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
593 spin_unlock_bh(&x->lock);
594 goto error_free;
595 }
596
597 skb_shinfo(skb)->nr_frags = 1;
598
599 page = pfrag->page;
600 get_page(page);
601 /* replace page frags in skb with new page */
602 __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len);
603 pfrag->offset = pfrag->offset + allocsize;
604 spin_unlock_bh(&x->lock);
605
606 sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1);
607 err = skb_to_sgvec(skb, dsg,
608 (unsigned char *)esph - skb->data,
609 assoclen + ivlen + esp->clen + alen);
610 if (unlikely(err < 0))
611 goto error_free;
612 }
613
614 if ((x->props.flags & XFRM_STATE_ESN))
615 aead_request_set_callback(req, 0, esp_output_done_esn, skb);
616 else
617 aead_request_set_callback(req, 0, esp_output_done, skb);
618
619 aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv);
620 aead_request_set_ad(req, assoclen);
621
622 memset(iv, 0, ivlen);
623 memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8),
624 min(ivlen, 8));
625
626 ESP_SKB_CB(skb)->tmp = tmp;
627 err = crypto_aead_encrypt(req);
628
629 switch (err) {
630 case -EINPROGRESS:
631 goto error;
632
633 case -ENOSPC:
634 err = NET_XMIT_DROP;
635 break;
636
637 case 0:
638 if ((x->props.flags & XFRM_STATE_ESN))
639 esp_output_restore_header(skb);
640 }
641
642 if (sg != dsg)
643 esp_ssg_unref(x, tmp);
644
645 if (!err && x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP)
646 err = esp_output_tail_tcp(x, skb);
647
648 error_free:
649 kfree(tmp);
650 error:
651 return err;
652 }
653 EXPORT_SYMBOL_GPL(esp_output_tail);
654
esp_output(struct xfrm_state * x,struct sk_buff * skb)655 static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
656 {
657 int alen;
658 int blksize;
659 struct ip_esp_hdr *esph;
660 struct crypto_aead *aead;
661 struct esp_info esp;
662
663 esp.inplace = true;
664
665 esp.proto = *skb_mac_header(skb);
666 *skb_mac_header(skb) = IPPROTO_ESP;
667
668 /* skb is pure payload to encrypt */
669
670 aead = x->data;
671 alen = crypto_aead_authsize(aead);
672
673 esp.tfclen = 0;
674 if (x->tfcpad) {
675 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb);
676 u32 padto;
677
678 padto = min(x->tfcpad, xfrm_state_mtu(x, dst->child_mtu_cached));
679 if (skb->len < padto)
680 esp.tfclen = padto - skb->len;
681 }
682 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
683 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
684 esp.plen = esp.clen - skb->len - esp.tfclen;
685 esp.tailen = esp.tfclen + esp.plen + alen;
686
687 esp.esph = ip_esp_hdr(skb);
688
689 esp.nfrags = esp_output_head(x, skb, &esp);
690 if (esp.nfrags < 0)
691 return esp.nfrags;
692
693 esph = esp.esph;
694 esph->spi = x->id.spi;
695
696 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
697 esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low +
698 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32));
699
700 skb_push(skb, -skb_network_offset(skb));
701
702 return esp_output_tail(x, skb, &esp);
703 }
704
esp_remove_trailer(struct sk_buff * skb)705 static inline int esp_remove_trailer(struct sk_buff *skb)
706 {
707 struct xfrm_state *x = xfrm_input_state(skb);
708 struct xfrm_offload *xo = xfrm_offload(skb);
709 struct crypto_aead *aead = x->data;
710 int alen, hlen, elen;
711 int padlen, trimlen;
712 __wsum csumdiff;
713 u8 nexthdr[2];
714 int ret;
715
716 alen = crypto_aead_authsize(aead);
717 hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
718 elen = skb->len - hlen;
719
720 if (xo && (xo->flags & XFRM_ESP_NO_TRAILER)) {
721 ret = xo->proto;
722 goto out;
723 }
724
725 if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2))
726 BUG();
727
728 ret = -EINVAL;
729 padlen = nexthdr[0];
730 if (padlen + 2 + alen >= elen) {
731 net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n",
732 padlen + 2, elen - alen);
733 goto out;
734 }
735
736 trimlen = alen + padlen + 2;
737 if (skb->ip_summed == CHECKSUM_COMPLETE) {
738 csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0);
739 skb->csum = csum_block_sub(skb->csum, csumdiff,
740 skb->len - trimlen);
741 }
742 ret = pskb_trim(skb, skb->len - trimlen);
743 if (unlikely(ret))
744 return ret;
745
746 ret = nexthdr[1];
747
748 out:
749 return ret;
750 }
751
esp_input_done2(struct sk_buff * skb,int err)752 int esp_input_done2(struct sk_buff *skb, int err)
753 {
754 const struct iphdr *iph;
755 struct xfrm_state *x = xfrm_input_state(skb);
756 struct xfrm_offload *xo = xfrm_offload(skb);
757 struct crypto_aead *aead = x->data;
758 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
759 int ihl;
760
761 if (!xo || !(xo->flags & CRYPTO_DONE))
762 kfree(ESP_SKB_CB(skb)->tmp);
763
764 if (unlikely(err))
765 goto out;
766
767 err = esp_remove_trailer(skb);
768 if (unlikely(err < 0))
769 goto out;
770
771 iph = ip_hdr(skb);
772 ihl = iph->ihl * 4;
773
774 if (x->encap) {
775 struct xfrm_encap_tmpl *encap = x->encap;
776 struct tcphdr *th = (void *)(skb_network_header(skb) + ihl);
777 struct udphdr *uh = (void *)(skb_network_header(skb) + ihl);
778 __be16 source;
779
780 switch (x->encap->encap_type) {
781 case TCP_ENCAP_ESPINTCP:
782 source = th->source;
783 break;
784 case UDP_ENCAP_ESPINUDP:
785 case UDP_ENCAP_ESPINUDP_NON_IKE:
786 source = uh->source;
787 break;
788 default:
789 WARN_ON_ONCE(1);
790 err = -EINVAL;
791 goto out;
792 }
793
794 /*
795 * 1) if the NAT-T peer's IP or port changed then
796 * advertize the change to the keying daemon.
797 * This is an inbound SA, so just compare
798 * SRC ports.
799 */
800 if (iph->saddr != x->props.saddr.a4 ||
801 source != encap->encap_sport) {
802 xfrm_address_t ipaddr;
803
804 ipaddr.a4 = iph->saddr;
805 km_new_mapping(x, &ipaddr, source);
806
807 /* XXX: perhaps add an extra
808 * policy check here, to see
809 * if we should allow or
810 * reject a packet from a
811 * different source
812 * address/port.
813 */
814 }
815
816 /*
817 * 2) ignore UDP/TCP checksums in case
818 * of NAT-T in Transport Mode, or
819 * perform other post-processing fixes
820 * as per draft-ietf-ipsec-udp-encaps-06,
821 * section 3.1.2
822 */
823 if (x->props.mode == XFRM_MODE_TRANSPORT)
824 skb->ip_summed = CHECKSUM_UNNECESSARY;
825 }
826
827 skb_pull_rcsum(skb, hlen);
828 if (x->props.mode == XFRM_MODE_TUNNEL)
829 skb_reset_transport_header(skb);
830 else
831 skb_set_transport_header(skb, -ihl);
832
833 /* RFC4303: Drop dummy packets without any error */
834 if (err == IPPROTO_NONE)
835 err = -EINVAL;
836
837 out:
838 return err;
839 }
840 EXPORT_SYMBOL_GPL(esp_input_done2);
841
esp_input_done(struct crypto_async_request * base,int err)842 static void esp_input_done(struct crypto_async_request *base, int err)
843 {
844 struct sk_buff *skb = base->data;
845
846 xfrm_input_resume(skb, esp_input_done2(skb, err));
847 }
848
esp_input_restore_header(struct sk_buff * skb)849 static void esp_input_restore_header(struct sk_buff *skb)
850 {
851 esp_restore_header(skb, 0);
852 __skb_pull(skb, 4);
853 }
854
esp_input_set_header(struct sk_buff * skb,__be32 * seqhi)855 static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi)
856 {
857 struct xfrm_state *x = xfrm_input_state(skb);
858 struct ip_esp_hdr *esph;
859
860 /* For ESN we move the header forward by 4 bytes to
861 * accommodate the high bits. We will move it back after
862 * decryption.
863 */
864 if ((x->props.flags & XFRM_STATE_ESN)) {
865 esph = skb_push(skb, 4);
866 *seqhi = esph->spi;
867 esph->spi = esph->seq_no;
868 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi;
869 }
870 }
871
esp_input_done_esn(struct crypto_async_request * base,int err)872 static void esp_input_done_esn(struct crypto_async_request *base, int err)
873 {
874 struct sk_buff *skb = base->data;
875
876 esp_input_restore_header(skb);
877 esp_input_done(base, err);
878 }
879
880 /*
881 * Note: detecting truncated vs. non-truncated authentication data is very
882 * expensive, so we only support truncated data, which is the recommended
883 * and common case.
884 */
esp_input(struct xfrm_state * x,struct sk_buff * skb)885 static int esp_input(struct xfrm_state *x, struct sk_buff *skb)
886 {
887 struct crypto_aead *aead = x->data;
888 struct aead_request *req;
889 struct sk_buff *trailer;
890 int ivlen = crypto_aead_ivsize(aead);
891 int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen;
892 int nfrags;
893 int assoclen;
894 int seqhilen;
895 __be32 *seqhi;
896 void *tmp;
897 u8 *iv;
898 struct scatterlist *sg;
899 int err = -EINVAL;
900
901 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen))
902 goto out;
903
904 if (elen <= 0)
905 goto out;
906
907 assoclen = sizeof(struct ip_esp_hdr);
908 seqhilen = 0;
909
910 if (x->props.flags & XFRM_STATE_ESN) {
911 seqhilen += sizeof(__be32);
912 assoclen += seqhilen;
913 }
914
915 if (!skb_cloned(skb)) {
916 if (!skb_is_nonlinear(skb)) {
917 nfrags = 1;
918
919 goto skip_cow;
920 } else if (!skb_has_frag_list(skb)) {
921 nfrags = skb_shinfo(skb)->nr_frags;
922 nfrags++;
923
924 goto skip_cow;
925 }
926 }
927
928 err = skb_cow_data(skb, 0, &trailer);
929 if (err < 0)
930 goto out;
931
932 nfrags = err;
933
934 skip_cow:
935 err = -ENOMEM;
936 tmp = esp_alloc_tmp(aead, nfrags, seqhilen);
937 if (!tmp)
938 goto out;
939
940 ESP_SKB_CB(skb)->tmp = tmp;
941 seqhi = esp_tmp_extra(tmp);
942 iv = esp_tmp_iv(aead, tmp, seqhilen);
943 req = esp_tmp_req(aead, iv);
944 sg = esp_req_sg(aead, req);
945
946 esp_input_set_header(skb, seqhi);
947
948 sg_init_table(sg, nfrags);
949 err = skb_to_sgvec(skb, sg, 0, skb->len);
950 if (unlikely(err < 0)) {
951 kfree(tmp);
952 goto out;
953 }
954
955 skb->ip_summed = CHECKSUM_NONE;
956
957 if ((x->props.flags & XFRM_STATE_ESN))
958 aead_request_set_callback(req, 0, esp_input_done_esn, skb);
959 else
960 aead_request_set_callback(req, 0, esp_input_done, skb);
961
962 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv);
963 aead_request_set_ad(req, assoclen);
964
965 err = crypto_aead_decrypt(req);
966 if (err == -EINPROGRESS)
967 goto out;
968
969 if ((x->props.flags & XFRM_STATE_ESN))
970 esp_input_restore_header(skb);
971
972 err = esp_input_done2(skb, err);
973
974 out:
975 return err;
976 }
977
esp4_err(struct sk_buff * skb,u32 info)978 static int esp4_err(struct sk_buff *skb, u32 info)
979 {
980 struct net *net = dev_net(skb->dev);
981 const struct iphdr *iph = (const struct iphdr *)skb->data;
982 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2));
983 struct xfrm_state *x;
984
985 switch (icmp_hdr(skb)->type) {
986 case ICMP_DEST_UNREACH:
987 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
988 return 0;
989 break;
990 case ICMP_REDIRECT:
991 break;
992 default:
993 return 0;
994 }
995
996 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
997 esph->spi, IPPROTO_ESP, AF_INET);
998 if (!x)
999 return 0;
1000
1001 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
1002 ipv4_update_pmtu(skb, net, info, 0, IPPROTO_ESP);
1003 else
1004 ipv4_redirect(skb, net, 0, IPPROTO_ESP);
1005 xfrm_state_put(x);
1006
1007 return 0;
1008 }
1009
esp_destroy(struct xfrm_state * x)1010 static void esp_destroy(struct xfrm_state *x)
1011 {
1012 struct crypto_aead *aead = x->data;
1013
1014 if (!aead)
1015 return;
1016
1017 crypto_free_aead(aead);
1018 }
1019
esp_init_aead(struct xfrm_state * x)1020 static int esp_init_aead(struct xfrm_state *x)
1021 {
1022 char aead_name[CRYPTO_MAX_ALG_NAME];
1023 struct crypto_aead *aead;
1024 int err;
1025
1026 err = -ENAMETOOLONG;
1027 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)",
1028 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME)
1029 goto error;
1030
1031 aead = crypto_alloc_aead(aead_name, 0, 0);
1032 err = PTR_ERR(aead);
1033 if (IS_ERR(aead))
1034 goto error;
1035
1036 x->data = aead;
1037
1038 err = crypto_aead_setkey(aead, x->aead->alg_key,
1039 (x->aead->alg_key_len + 7) / 8);
1040 if (err)
1041 goto error;
1042
1043 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
1044 if (err)
1045 goto error;
1046
1047 error:
1048 return err;
1049 }
1050
esp_init_authenc(struct xfrm_state * x)1051 static int esp_init_authenc(struct xfrm_state *x)
1052 {
1053 struct crypto_aead *aead;
1054 struct crypto_authenc_key_param *param;
1055 struct rtattr *rta;
1056 char *key;
1057 char *p;
1058 char authenc_name[CRYPTO_MAX_ALG_NAME];
1059 unsigned int keylen;
1060 int err;
1061
1062 err = -EINVAL;
1063 if (!x->ealg)
1064 goto error;
1065
1066 err = -ENAMETOOLONG;
1067
1068 if ((x->props.flags & XFRM_STATE_ESN)) {
1069 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
1070 "%s%sauthencesn(%s,%s)%s",
1071 x->geniv ?: "", x->geniv ? "(" : "",
1072 x->aalg ? x->aalg->alg_name : "digest_null",
1073 x->ealg->alg_name,
1074 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME)
1075 goto error;
1076 } else {
1077 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
1078 "%s%sauthenc(%s,%s)%s",
1079 x->geniv ?: "", x->geniv ? "(" : "",
1080 x->aalg ? x->aalg->alg_name : "digest_null",
1081 x->ealg->alg_name,
1082 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME)
1083 goto error;
1084 }
1085
1086 aead = crypto_alloc_aead(authenc_name, 0, 0);
1087 err = PTR_ERR(aead);
1088 if (IS_ERR(aead))
1089 goto error;
1090
1091 x->data = aead;
1092
1093 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
1094 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
1095 err = -ENOMEM;
1096 key = kmalloc(keylen, GFP_KERNEL);
1097 if (!key)
1098 goto error;
1099
1100 p = key;
1101 rta = (void *)p;
1102 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
1103 rta->rta_len = RTA_LENGTH(sizeof(*param));
1104 param = RTA_DATA(rta);
1105 p += RTA_SPACE(sizeof(*param));
1106
1107 if (x->aalg) {
1108 struct xfrm_algo_desc *aalg_desc;
1109
1110 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
1111 p += (x->aalg->alg_key_len + 7) / 8;
1112
1113 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
1114 BUG_ON(!aalg_desc);
1115
1116 err = -EINVAL;
1117 if (aalg_desc->uinfo.auth.icv_fullbits / 8 !=
1118 crypto_aead_authsize(aead)) {
1119 pr_info("ESP: %s digestsize %u != %hu\n",
1120 x->aalg->alg_name,
1121 crypto_aead_authsize(aead),
1122 aalg_desc->uinfo.auth.icv_fullbits / 8);
1123 goto free_key;
1124 }
1125
1126 err = crypto_aead_setauthsize(
1127 aead, x->aalg->alg_trunc_len / 8);
1128 if (err)
1129 goto free_key;
1130 }
1131
1132 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
1133 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
1134
1135 err = crypto_aead_setkey(aead, key, keylen);
1136
1137 free_key:
1138 kfree_sensitive(key);
1139
1140 error:
1141 return err;
1142 }
1143
esp_init_state(struct xfrm_state * x)1144 static int esp_init_state(struct xfrm_state *x)
1145 {
1146 struct crypto_aead *aead;
1147 u32 align;
1148 int err;
1149
1150 x->data = NULL;
1151
1152 if (x->aead)
1153 err = esp_init_aead(x);
1154 else
1155 err = esp_init_authenc(x);
1156
1157 if (err)
1158 goto error;
1159
1160 aead = x->data;
1161
1162 x->props.header_len = sizeof(struct ip_esp_hdr) +
1163 crypto_aead_ivsize(aead);
1164 if (x->props.mode == XFRM_MODE_TUNNEL)
1165 x->props.header_len += sizeof(struct iphdr);
1166 else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6)
1167 x->props.header_len += IPV4_BEET_PHMAXLEN;
1168 if (x->encap) {
1169 struct xfrm_encap_tmpl *encap = x->encap;
1170
1171 switch (encap->encap_type) {
1172 default:
1173 err = -EINVAL;
1174 goto error;
1175 case UDP_ENCAP_ESPINUDP:
1176 x->props.header_len += sizeof(struct udphdr);
1177 break;
1178 case UDP_ENCAP_ESPINUDP_NON_IKE:
1179 x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32);
1180 break;
1181 #ifdef CONFIG_INET_ESPINTCP
1182 case TCP_ENCAP_ESPINTCP:
1183 /* only the length field, TCP encap is done by
1184 * the socket
1185 */
1186 x->props.header_len += 2;
1187 break;
1188 #endif
1189 }
1190 }
1191
1192 align = ALIGN(crypto_aead_blocksize(aead), 4);
1193 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead);
1194
1195 error:
1196 return err;
1197 }
1198
esp4_rcv_cb(struct sk_buff * skb,int err)1199 static int esp4_rcv_cb(struct sk_buff *skb, int err)
1200 {
1201 return 0;
1202 }
1203
1204 static const struct xfrm_type esp_type =
1205 {
1206 .owner = THIS_MODULE,
1207 .proto = IPPROTO_ESP,
1208 .flags = XFRM_TYPE_REPLAY_PROT,
1209 .init_state = esp_init_state,
1210 .destructor = esp_destroy,
1211 .input = esp_input,
1212 .output = esp_output,
1213 };
1214
1215 static struct xfrm4_protocol esp4_protocol = {
1216 .handler = xfrm4_rcv,
1217 .input_handler = xfrm_input,
1218 .cb_handler = esp4_rcv_cb,
1219 .err_handler = esp4_err,
1220 .priority = 0,
1221 };
1222
esp4_init(void)1223 static int __init esp4_init(void)
1224 {
1225 if (xfrm_register_type(&esp_type, AF_INET) < 0) {
1226 pr_info("%s: can't add xfrm type\n", __func__);
1227 return -EAGAIN;
1228 }
1229 if (xfrm4_protocol_register(&esp4_protocol, IPPROTO_ESP) < 0) {
1230 pr_info("%s: can't add protocol\n", __func__);
1231 xfrm_unregister_type(&esp_type, AF_INET);
1232 return -EAGAIN;
1233 }
1234 return 0;
1235 }
1236
esp4_fini(void)1237 static void __exit esp4_fini(void)
1238 {
1239 if (xfrm4_protocol_deregister(&esp4_protocol, IPPROTO_ESP) < 0)
1240 pr_info("%s: can't remove protocol\n", __func__);
1241 xfrm_unregister_type(&esp_type, AF_INET);
1242 }
1243
1244 module_init(esp4_init);
1245 module_exit(esp4_fini);
1246 MODULE_LICENSE("GPL");
1247 MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP);
1248